Coil spring grinder



Jan. 9, 1968 M. GEISSMANN ETAL 3,362,110

COIL SPRING GRINDER I Filed Oct. 2, 1964 2 Sheets-Sheet 2 31 Fig. 2

29 'NVENTORS MARCO GEISSMANN Immanuel. 5T RAU B p'rromveys United StatesPatent 3,362,110 COIL SPRING GRINDER Marco Geissmann, Kilchberg, Zurich,and Immanuel Straub, Wangs, Saint Gall, Switzerland, assignors toStorenund Maschinenfabrik Emil Schenker A.-G., Schonenwerd, SwitzerlandFiled Oct. 2, 1964, Ser. No. 401,166

Claims priority, application Switzerland, Oct. 4, 1963,

1 Claim. (Cl. 51--124) This invention relates to a machine for surfacegrinding the end faces of workpieces, particularly the ends ofcompression springs.

In order to permit uniform loading of compression springs it isnecessary that their end faces are situated each in a plane normal tothe longitudinal axis of the spring. To this end the contact faces ofcompression springs such as are used for example in vehicles mustnecessarily be face ground. To achieve this working process a springwhich is normally held between clamping means and guided at right angleswith respect to the working face of the grinding wheel, is pressedagainst the said wheel by means of a uniformly advancing spindle. Suchuniform advance or feed has the disadvantage, at least at the beginningof the operation where the cross section of the work-piece is small, tobe too slow, while at the end where the cross section to be worked islarge, the feed is too rapid. Thus, there is always a risk that the endof the workpiece will become incandescent, and therefore will lose itsrequired shape. Furthermore the grinding capacity of the grinding wheelis gradually decreasing while on the other hand the feed rate remainsconstant. This will unavoidably result in an overloading and destructionof the grinding wheel.

A further object of the invention is the provision of an improvedmachine for surface grinding the ends of workpieces of the type referredto above. According to the invention this grinding machine comprises aframe and a rotatable shaft supported therein, a grinding wheel fixed onsaid rotatable shaft, driving means for said shaft, a swinging carriermeans for the workpieces and means for applying the workpieces againstthe said grinding wheel with a substantially constant pressure.

Further objects and advantages will be more apparent from the followingdescription of the accompanying drawings in which:

FIG. 1 is an elevational View of a grinding machine in accordance withthe invention;

FIG. 2 is a side view of the machine shown in FIG. 1.

A grinding machine of known type comprises a housing 1 in which a shaft2 is rotatably supported. A swinging arm 3, provided at its free lowerend with a worktable 4, is pivotally mounted on shaft 2 for swinging infront of face 5a of a grinding wheel 5. A pair of clamping jaws 6, 7 arefixed on the worktable 4 on opposite sides of the longitudinal axis ofarm 3. A second pair of movable clamping jaws 8, 9 are provided belowthe said first pair 6, 7 and exactly opposite thereof. The jaws 8, 9 aresecured on rods 10, 11 which in turn are slidably guided incorrespondingly shaped vertical bores 16a, 11a in arm 3 whereby uponactuation of two spindles 14, 15 provided each with a hand wheel 12 and13, respectively, in either one or the other direction, the jaws 8, 9are displaced to or from the corresponding fixed jaws 6, 7. The solepurpose of these coarse adjusting means is to guide and clamp thework-pieces. In the embodiment shown, the left hand clamping device isholding a pair of springs 16 of small diameter, while the other clampingdevice is centering and holding a pair of springs 17 of relatively greatdiameter. The working or contact surfaces of the jaws 6 to 9 areV-shaped thus permitting to securely hold springs having diametersvarying in a very wide range. The clamping devices are provided withinserts 18, 19 and 20, 21, the removal thereof permitting the fixing ofsprings of still greater diameter.

The free ends of spindles 14, 15, i.e. the ends opposite the said :handwheels 12, 13, are connected each by an intermediate piece 22 and 23,respectively, to one of the piston rods 24, 25 of double-actingpneumatic or hydraulic jacks 26, 27. The proper clamping of the springs16, 17 is effected by the withdrawal of pistons 24, 25 into thecylinders of jacks 26, 27.

The lower portion of the grinding wheel 5 penetrates into a container 28partially filled with a cooling liquid 29, such as for example water.During rotation in the direction indicated by arrow 30, a certain amountof water is entrained by wheel 5 thus cooling the different workingsites as will be described in more detail below. Channels 31, 32 andbaffles are provided for directing the cooling liquid to the desiredplaces. Thus bafile 33 at the upper end of channel 31 is directing thecooling liquid to the right hand working place. The other working placeis cooled with liquid coming from outlet 34 at the end of channel 32.The shaft 2 extends through housing 1 and has a swinging lever 35 fixedthereon. This lever 35 is driven by the reciprocating piston rod 36 of apneumatically actuated jack 37. Suitable valve means of known type (notrepresented in the drawing) feed pressure air alternatively into thecylinder spaces on either side of piston 36a of jack 37, thereby causinga swinging movement of determined length of the arm 3.

A guiding rod 38 (FIG. 2) rigidly connected to the shaft 2 by arms 39,4d and thus effecting the same swinging movement is provided and passesthrough a bore in the upper portion of arm 3 for pushing the latteragainst the face 5a of the grinding wheel 5. A double-acting pneumaticjack 41 is mounted on the arm 3 between the guiding rod 38 and the shaft2. A piston 42 is rigidly connected to the arm 40 and may be extendedand retracted to move the swinging arm 3, which is slidingly held onshaft 2 and guiding rod 38, to or from the grinding wheel 5. Adjustablestop'per means 44, 45 are provided for limiting the feed course of arm3. These stoppers 44, 45, when in their end positions, are actuating acontact 46 causing the swinging arm 3 to stop its movement.

The grinding machine operates as follows: The springs 16, 17 are fixedin the clamping devices by actuation of the hand wheels 12, 13 followedby the actuation of the cylinders 26, 27 Thereafter the swinging arm 3is reciprocated in front of the grinding wheel 5 by the saidpneumatically actuated jack 37. This swinging movement of arm 3 movesthe springs 16, 17 over the whole working face of wheel 5 therebycausing a continuous abrasion of the wheel. The pneumatically controlledfeed by the pneumatic jack 41 causes the springs to be applied againstthe front face 5a of wheel 5 With a substantially constant pressure. Thedifferent working areas are simultaneously subjected to an intensivecooling by the cooling liquid which is entrained by the rotating wheel 5and, owing to the occurring centrifugal forces, fed through the channels31, 32 and therefrom directed to the working areas. When the swingingarm 3 reaches its end position, the pressure is still maintained duringa short period in order to permit the ends of the springs to besubjected to a precise surface grinding.

It will of course be understood that various changes in details ofconstruction and arrangement of parts may be made by those skilled inthe art without departing from the spirit of the invention as set forthin the appended claim.

We claim:

1. A grinding machine particularly for grinding coil springs, comprisinga rotatable grinding Wheel, a workpiece supporting swing arm, meanspivotally mounting said swing arm for pivotal movement about an axissubstantially perpendicular to said grinding wheel for swinging saidswing arm backwardly and forwardly adjacent one side face of saidgrinding wheel, workpiece clamping jaws Carried on said swing armarranged for holding a workpiece substantially normal to said grindingwheel, adjusting means connected to said jaws for opening said jaws forclamping them around a workpiece, such as a spring, and for holding theworkpiece substantially normal to said grinding wheel, fluid pressureoperated means connected to said swing arm for pivoting said swing armto cause movement of said jaws with the workpiece therein from side toside over said grinding wheel, fluid pressure holding means connected tosaid swing arm and urging said swing arm in a direction toward saidgrinding wheel to hold the workpiece in said jaws against said grindingwheel with a constant pressure, a shaft member pivotally supporting saidswing arm disposed adjacent and substantially perpendicular to a sideface of said grinding wheel, said swing arm being slidable along saidshaft,

and a crank frame pivotally supported on said shaft and having an upperspindle member extending through said swing arm and being parallel tosaid shaft, said fluid pressure holding means including a fluid cylindermember carried by said swing arm having a piston engageable with saidframe and being movable to displace said swing arm away from said frame.

References Cited UNITED STATES PATENTS 665,380 1/1901 Barnes 512671,436,860 11/1922 Church 26932 2,021,602 11/1935 Jackson 51124 2,095,43810/1937 Hall 51124 2,104,345 1/1938 Holhut 51124 2,127,877 8/1938Maglott 51233 X FOREIGN PATENTS 504,388 7/1920 France.

HAROLD D. WHITEHEAD, Primary Examiner.

1. A GRINDING MACHINE PARTICULARLY FOR GRINDING COIL SPRINGS, COMPRISINGA ROTATABLE GRINDING WHEEL, A WORKPIECE SUPPORTING SWING ARM, MEANSPIVOTALLY MOUNTING SAID SWING ARM FOR PIVOTAL MOVEMENT ABOUT AN AXISSUBSTANTIALLY PERPENDICULAR TO SAID GRINDING WHEEL FOR SWINGING SAIDSWING ARM BACKWARDLY AND FORWARDLY ADJACENT ONE SIDE FACE OF SAIDGRINDING WHEEL, WORKPIECE CLAMPING JAWS CARRIED ON SAID SWING ARMARRANGED FOR HOLDING A WORKPIECE SUBSTANTIALLY NORMAL TO SAID GRINDINGWHEEL, ADJUSTING MEANS CONNECTED TO SAID JAWS FOR OPENING SAID JAWS FORCLAMPING THEM AROUND A WORKPIECE, SUCH AS A SPRING, AND FOR HOLDING THEWORKPIECE SUBSTANTIALLY NORMAL TO SAID GRINDING WHEEL, FLUID PRESSUREOPERATED MEANS CONNECTED TO SAID SWING ARM FOR PIVOTING SAID SWING ARMTO CAUSE MOVEMENT OF SAID JAWS WITH THE WORKPIECE THEREIN FROM SIDE TOSIDE OVER SAID GRINDING WHEEL, FLUID PRESSURE HOLDING MEANS CONNECTED TOSAID SWING ARM AND URGING SAID SWING ARM IN A DIRECTION TOWARD SAIDGRINDING WHEEL TO HOLD THE WORKPIECE IN SAID JAWS AGAINST SAID GRINDINGWHEEL WITH A CONSTANT PRESSURE, A SHAFT MEMBER PIVOTALLY SUPPORTING SAIDSWING ARM DISPOSED ADJACENT AND SUBSTANTIALLY PERPENDICULAR TO A SIDEFACE OF SAID GRINDING WHEEL, SAID SWING ARM BEING SLIDABLE ALONG SAIDSHAFT, AND A CRANK FRAME PIVOTALLY SUPPORTED ON SAID SHAFT AND HAVING ANUPPER SPINDLE MEMBER EXTENDING THROUGH SAID SWING ARM AND BEING PARALLELTO SAID SHAFT, SAID FLUID PRESSURE HOLDING MEANS INCLUDING A FLUIDCYLINDER MEMBER CARRIED BY SAID SWING ARM HAVING A PISTON ENGAGEABLEWITH SAID FRAME AND BEING MOVABLE TO DISPLACE SAID SWING ARM AWAY FROMSAID FRAME.